This invention relates to an apparatus for dispensing nutritional substances enterically. This is considered the physiologically most effective method to improve the nutrition of underfed patients and to insure a prognosis of favorable recovery.
In contrast to parenteral nutrition, which requires an invasive access to the patient, enteric nutrition uses the natural body cavity of the gastro-intestinal area to dispense nutrition. A probe is introduced into the body cavity and placed so that the nutritional fluid is dispensed in a specific area, for instance in the stomach area, the duodenum or jejuneum, and reabsorbed. The probe is connected to a storage container, containing the nutritional substance, mostly an industrially manufactured product. Heretofore, generally application was accomplished by means of a common hose clamp which allowed no exact dosage of the nutritional substance into the gastro-intentinal area. Common complications by this method of feeding are diarrhea and other gastro-intestinal side effects. These complications are primarily due to the unsatisfactory method for regulating the amount and speed of the nutrition. Based on these factors, the invention has as an object to provide an apparatus by means of which, and according to physiological demands, nutritional substance can be directed to the specific area of application. Depending on the way it is being used, this should enable a constant or quasi-constant output, for instance into the duodenum or jejuneum, or a bole application, for instance into the stomach. Furthermore, as a consequence of its medical importance, the invention has a high degree of reliability and is easy to operate. Finally, it is necessary that such an apparatus is constructed in such a way that it can easily and without operational disturbances be carried around by the patient.
This goal is achieved, according to the invention, by means of an electronically controlled, electrically powered pump, running at a fixed speed of rotation when turned on or operating, and which can be run continuously or at intervals with the operating and non-operating times being pre-selected by the electrical control system.
A pump which is run and controlled in such a manner maximizes the speed of rotation and the motor thus demonstrates a particularly favorable degree of efficiency which is important, especially when operating by battery. Since the operating and non-operating times can be regulated, the apparatus can be adjusted especially well to the various physiological demands and requirements, and, at the same time, it enables a very exact supply of nutrition.
The invention further provides for a roller pump. Such pumps in themselves are well known and are especially suited for use according to the invention, due to the fact that the supplied fluid is not brought into a sometimes hygienically problematic pump body, but rather is supplied through the pump inside a conduit or tube. It is of advantage that an intermittent or incremental motor is used to run the pump, enabling a particularly exact control Thus the intervals of operation of the motor can be coordinated with the dimensions of the pump plate or the roller pump in a suitable fashion. It is of further advantage that the power supply can be either from a battery or line current. Thus on the one hand, the mobility of the patient is guaranteed by the battery operation and, on the other hand, the batteries can be spared or even charged in the case of a stationary feeding situation.
It is within the framework of the invention that the electronic control equipment comprises independent, separately adjustable time unit oscillators with supplemented adjustable dividers. Through these time units, the interval lengths of the standing or non-operating and operating times are pre-selected. The design or operation chosen in the invention assures problem-free adjustability over a wide range. The independent adjustability of operating and non-operating times creates physiologically favorable conditions.
It is of particular advantage that the time units are connected to an adjustor or commutator to adjust the set-up as to length of time. In this way it is possible to achieve, by means of the prescribed, easily comprehensible scale, an exact adjustment for such varied orders of magnitude as seconds, on the one hand, and several hours, on the other hand.
Advantageously the motor may be connected to a meter, controlled by a signal given by the pump motor during the time of operation. By this meter, the total time of operation of the motor is covered, which corresponds proportionally to the supplied amount of nutritional substance.
Advantageous also is a report and alarm system attached to the meter. Because of this, the personnel operating the machine can read the already supplied amount of fluid, or set the predetermined amount in advance, so that either an automatic stop of the motor is effected after having reached the prescribed amount, or an accoustic and/or optical alarm signal is operated.
The invention also contains provisions for an arrangement to turn off the power electronics during the non-operating intervals. Through this the consumption of electricity is markedly reduced.
A transistor switch in the electrical current branch can be used to disconnect the apparatus.
It is advantageous that an indicating device is constructed in such a way that the indications ensue in an impulse-like manner, preferably at the magnitude of a couple of waves per second. Such impulse-like indicators are characterized by, on the one hand, lower consumption of current and, on the other hand, by a higher degree of attention, and are clearly noticeable even in bright rooms at a not too high degree of brightness. A luminous diode can be used as the indicating device.
It is advantageous that the plate, which carries the rollers of the roller pump and which is driven by an electric motor, is made of glass fiber reinforced polyamide. Thus a high degree of firmness and resistance against deformation is achieved by using a material which is also safe in every respect from a hygienic standpoint.
The plate is further provided with eight actuators over which are located slide sleeves which serve as rollers. These slide sleeves are preferably made out of polyacetale. It is, however, further possible that it will turn out to be of advantage that the slide sleeves may be arranged rotatary in a cage guide bearing. The thus achieved minimal friction of the rollers lowers the initial starting effort of the motor and thus its use of energy.
Under certain circumstances, it can further be of advantage that the rotating pump part is equipped with slide and contact sleeves in the fashion of planetary gearing. It is of advantage that between the sleeves of the roller pump and the nutrition transporting tube is placed a flexible band with an upper surface of a very low friction coefficient. With this arrangement, the rotating sleeves do not directly contact the tube, damaging it, and at the same time there is also avoided a possible accelerator effect, through which the tube as a whole would be moved in the apparatus.
The invention provides that the sliding body, against which the conveyor tube is pressed by the slide sleeves is designed as a pivoted lever. Thus it is readily possible to insert or remove the conveyor tube from the apparatus at the beginning and the end of the feeding process.
It is advantageous that the sliding body is pushed into the pump arrangement by means of a lever connected to an eccentric. Thus the sliding body can be brought into the working position by a turning knob with exactly determined end positions.
It is in this connection an advantage, if in order to produce a defined initial pressure, a spring arrangement is used.
For practical use, it is finally of advantage if the arrangement suggested by the invention has a hanger which enables a problem-free placement at, for instance, the bed of the patient.
Other features which are considered characteristic of the invention are set forth in the appended claims.
Although the invention is illustrated and described in relationship to specific embodiments, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.